Planet with British weather found 20 light years away

A group of boffins claims to have spied the "first discovered terrestrial-mass exoplanet in the habitable zone", the BBC reports.

The planet in question is orbiting the much-studied star Gliese 581, some 20 light-years away in the constellation Libra. Of the possible worlds circling the red M-class sun, Gliese 581d had already been proposed as a repository of water, although studies suggested its distance from the solar system's centre means it would be too cold for liquid H2O.

A rival for scientists' affections, Gliese 581g, then took centre stage as perhaps the first known habitable alien world, but the very existence of that planet has been called into serious doubt.

The astronomers from the Institut Pierre Simon Laplace in Paris have now re-evaluated Gliese 581d, declaring it the first Blighty-like exoplanet – cold, rainy and just about capable of supporting life. Their simulations point to a dense, CO2 atmosphere which would provide "a signicant greenhouse effect" to raise the mean global temperature above 0°C.

There are a couple of minor impediments to human colonisation of Gliese 581d, however. The atmosphere is, in common with our own Middlesbrough, toxic. The planet is also probably tidally locked to its sun, meaning one side in permanent darkness, and the other with light perpetually struggling to penetrate the fug.

Nonetheless, team member Robin Wordsworth said the findings were "tantamount to a first definitive claim for a habitable exoplanet".

He said: "This discovery is important because it's the first time climate modellers have proved that the planet is potentially habitable, and all observers agree that the exoplanet exists.

"The Gliese system is particularly exciting to us as it's very close to Earth, relatively speaking. So with future generations of telescopes, we'll be able to search for life on Gliese 581d directly."

If we do in one day spy life on the planet, it's entirely probable it will be preparing to invade Earth in response to Bebo's ill-advised 2008 decision to direct a radio message at the Gliese 581 system. This contained a provocative selection of "text and imagery submitted by devotees of the web-2.0 teenybopper portal", as we previously described it.

The latest findings on Gliese 581d can be found right here (nine-page PDF/1.2MB). ®